In stores such as convenience stores, loss occurs at an opportunity if there is a defect in the display state of a product displayed on display shelves, that is, the display of a product is disturbed or there is a shortage of a product, and this opportunity loss has a significant impact on sales in the store, such that in a case where there is a defect in the display state of a product, it is necessary to promptly implement a product management work (an arranging work or a replenishing work) to resolve the defect.
As a technique relating to such a product management work, in the related art, a technique is known which determines necessity of the product management work, based on the captured image of a display area and makes a notification instructing a product arranging work (see PTLs 1 and 2). In particular, in the technique disclosed in PTL 1, a reference display pattern is set based on the display state of a desired product, the reference display pattern and the actual display state of a product are compared, and the display state of the product may be evaluated, based on the similarity between them. In the technique disclosed in PTL 2, a representative shape to be inserted between a boundary line that defines the outer edge of the product present region and a boundary line of a product absence region in the inside of the above boundary line is obtained, and the degree of appropriateness (face-up degree) of the display state of the product is calculated based on the area of the representative shape.